Structure and Function of Skin

Question 1

What adnexal structures does the skin contain?

Answer 1

Hair
Nails
Glands
Sensory structures

Question 2

What is the epidermis mainly made up from?

Answer 2

Keratocytes (90%)

Question 3

What in the dermis is lost as you get older?

Answer 3

Thickness

Question 4

Where do the adnexal structures lie in the skin?

Answer 4

Dermis

Question 5

What are the layers of the dermis?

Answer 5

1. Stratum basale
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum

Question 6

What happens as kertocytes mature?

Answer 6

They lose their nucleus and flatten

Question 7

In normal skin, how long does it take for keratocytes to mature?

Answer 7

30 days

Question 8

Why is the skin able to regenerate?

Answer 8

Stem cells present in the skin

Question 9

Where is the stratum corneum thin?

Answer 9

Eyelids

Question 10

Where is the stratum corneum thick?

Answer 10

Palms and soles

Question 11

What does the nail help?

Answer 11

Fine sensory motor tasks

Question 12

Function of the nail matrix

Answer 12

Causes the nail plate (flat keratin) to be generated

Question 13

What is the cuticle?

Answer 13

Skin at the bottom of the nail

Question 14

Function of the cuticle

Answer 14

Protects nail matrix from infection

Question 15

What are the stages of the hair cycle?

Answer 15

Anagen
Catagen
Telogen

Question 16

Features of anagen

Answer 16

Active growing phase

Question 17

What % of hair is growing at any one time?

Answer 17

80-90%

Question 18

Features of catagen

Answer 18

2-3 weeks phase of growth stops / follicle shrinks

Question 19

What % of hairs are in catagen?

Answer 19

1-3%

Question 20

Features of telogen

Answer 20

Resting phase for 1-4 months

Old hair sheds and anagen starts again

Question 21

What % of hairs in a normal scalp are in telogen?

Answer 21

10%

Question 22

What is telogen pleurium? When would this occur?

Answer 22

A condition where all of the hairs shed at one time

Would occur in a traumatic experience e.g. sepsis

Question 23

Functions of the skin

Answer 23

Thermoregulation 
Skin immune system 
Barrier 
Sensation 
Vitamin D synthesis
Interpersonal communication

Question 24

How does the skin provide thermoregulation?

Answer 24

Insulation
- shiver / goosebumps
- contraction of hairs
Heat transfer

Question 25

What is the skin a barrier against?

Answer 25

Mechanical Chemical microorganisms UV light

Question 26

What does the skin keep in?

Answer 26

Water Electrolytes Macromolecules

Question 27

What % of the population is affected by a skin disease?

Answer 27

22-30%

Question 28

Causes of skin disease

Answer 28

``` Temperature UV Chemical - allergen or irritant Infection Trauma Systemic disease Genetics Drugs ```

Question 29

Where is affected in a photosensitivity skin disease?

Answer 29

Exposed sites - neck line - arms

Question 30

Pathology of Bullous pemphigoid

Answer 30

Autoimmune Desmosomes stop being recognised and immune system comes to attack it Blistering and epidermis reaches up

Question 31

Definition of a small skin lesion

Answer 31

< 5mm

Question 32

Definition of a macule

Answer 32

Small circumscribed area

Question 33

Definition of a patch

Answer 33

Larger circumscribed area

Question 34

Definition of a papule

Answer 34

Small raised area

Question 35

Definition of a plaque

Answer 35

Larger raised area

Question 36

Definition of a vesicle

Answer 36

Small fluid filled lesion < 0.5cm

Question 37

Definition of a bullae

Answer 37

Large fluid filled lesion > 0.5cm

Question 38

Definition of a pustule

Answer 38

Small pus filled

Question 39

Definition of an abscess

Answer 39

Large pus filled

Question 40

Definition of an erosion

Answer 40

Superficial loss of epidermis

Question 41

Definition of an ulcer

Answer 41

Loss of epidermis and dermis

Question 42

Two types of distribution of a skin lesion

Answer 42

Isolated / solitary / single | Multiple

Question 43

Another name for hyperlipidaemia

Answer 43

Eruptive xanthoma

Question 44

Associations of acanthosis nigricans

Answer 44

Insulin resistance Obesity Malignancy T2DM

Question 45

Where is acanthosis nigricans found?

Answer 45

Flexural distribution

Question 46

Presentation of acanthosis nigricans

Answer 46

Hyperkeratosis Hyperpigmentation Papules Velvety appearance

Question 47

What particular skin condition is commonly seen in thyroid conditions?

Answer 47

Pretibial myxoedema

Question 48

What investigations would be done if a bacterial infection is suspected?

Answer 48

Charcoal swab - then microscopy, cultures, sensitivities Can only be used on areas of infected skin and look for weeping areas / ulcers etc

Question 49

What type of bacterial infection would a charcoal swab not be useful in?

Answer 49

Cellulitis

Question 50

What investigations would be done if a viral infection is suspected?

Answer 50

Viral swab for PCR

Question 51

What investigations would be done if a fungal infection is suspected?

Answer 51

Skin scraping Nail clippings Hair sample Then fungal cultures